I've taken a list of English words, and examined each of them to see what they sound like (using the PHP metaphone function). This page lists the most common metaphone codes, along with their words. You can also search for a word of your own, and see which words sound similar - and which ones rhyme, and which ones alliterate.
lowboy lobo lobby looby lob lobe lab lib
cowboy lowboy boy buoy poboy doughboy
low alow blow blowy flow glow lowly plow slow